Monday, November 20, 2006

100 Years Young - Can an Organism 'Grow' Smaller and Younger?

100 Years Young:
Part I: Musings About the Drayan Life-Cycle

Part II: Is Aging an Inevitable Biological Fact?

Part III: Can an Organism 'Grow' Smaller and Younger?
Part IV: The Drayan Civilization

If you're ready to accept, or at least consider, that aging isn't a biological necessity, accepting the idea that things might grow smaller over time should be a relatively simple matter. At the same time, there are some logistical problems to work out. Consider the following comment from a book about how science-fiction writers can craft convincing alien life-forms: "Every creature I know of starts out as a smaller structure produced in the body of one or more adults of its kind. To become an adult itself, it must grow" (Aliens and Alien Societies, Stanley Schmidt).

Schmidt's comment that things "must grow" does make a lot of sense—and in principle I am inclined to agree with him. This illustrates our second instinctive objection to the Drayan life-cycle: A species cannot start fully grown, so the idea of a reverse life-cycle doesn't make any sense.

However, I would argue that this objection is rooted not in what we actually know about the Drayan, but in an overly-simplistic, overly-literal interpretation of what reverse aging means. While the episode gives few details about how reverse aging works, it is ridiculous to think it is as simple as playing a recording of "normal" growth in reverse. If that were the case the Drayan elder-children would have to continue growing younger and younger to the point of being embryos, zygotes, single cells . . .

There is no evidence that this is what happens. The episode suggests (although never shows) that after becoming "young children," they abruptly vanish—somehow transmuting into another form of life or into some kind of energy. If their end does not directly correspond to our beginning, then there is no reason to insist that their beginning directly corresponds to our end.

To put it another way, there is no reason to insist that in size or form they are born as fully grown old men and women with grey hair and wrinkles. The Drayan probably do have to start small and get bigger to be born, just as Schmidt states above. But beyond the point of reproduction and gestation, growth does not absolutely have to follow this trend in every aspect of a creature's life or all of the way to the end of that creature's life. There are examples of life right here on earth that directly or indirectly demonstrate this.

Life as We Know It
Butterflies - When a caterpillar turns into a butterfly, its organs liquefy. It then reassembles itself into what is essentially a completely different organism.

Talk about inconceivable.

If you didn't know anything about butterflies—if you hadn't been familiar with them from childhood on—the very notion that any species undergoes such a bizarre transformation would be difficult to accept as anything but science fiction.

Because we have been exposed to this process of metamorphosis all of our lives, it has become just another fact—the sky is blue, the grass is green, caterpillars turn into butterflies. But when we look at a butterfly's life-cycle for what it really is, we realize that such a radical process of growth and development is really far more unbelievable, far more shocking, than the suggestion that an organism (which retains the same basic shape, the same organs, the same internal functions) just happens to get smaller and more youthful over time. If we are willing to accept a universe where caterpillars turn into butterflies, we have to be willing to accept the possibility of just about any biological process—even reverse aging.

Migratory Birds - In preparation for their long flights, some species of migratory birds undergo a fascinating process of reverse growth. Internal organs, such as their digestive tract and even their brains actually grow smaller, thus reducing their overall weight for the long flight ahead. This illustrates that growth does not always mean getting bigger over time.

If individual organs can be programmed to grow smaller, couldn't the same be true of an organism as a whole? Our bodies are able to coordinate the growth of all of our organs simultaneously as we grow up; it would certainly be no more complicated for that process to be coordinated in reverse.

In fact one creature does exactly that . . .

Turritopsis nutricula
- That is the scientific name for a jellyfish-like creature. After it matures and reproduces, this creature completely reverts to a younger state and starts its life over again. (Read more here and here.) So speculation and extrapolation aside, we do have here on earth proof that there is such a thing as reverse aging.

If only we could get poor turritopsis nutricula a new name. Perhaps Drayan would be most appropriate.

A Speculative Mode of Reproduction
The seemingly simple sponge has a particularly remarkable ability. If a live sponge is ground apart, the cells will group together and reform the original animal. If two sponges are ground up together, the cells will eventually separate and reform the two original sponges. National Geographic News states: "No other plant or animal can resurrect itself this way."

This suggests an intriguing possibility that could circumvent the 'start small and grow large' rule'—at least in the realm of science fiction—if we turn this unique ability into a mode of reproduction.

Imagine an alien species that is constantly shedding living cells, similar to the way humans are constantly shedding skin cells. Now imagine if those cells could, under the right circumstances, coalesce into a complete, functioning organism. Admittedly this is a bizarre concept, but not significantly more bizarre than what the sponge already does. Such a species could potentially produce full-grown offspring.

Obviously, nothing directly suggests this is how the Drayan reproduce, but this is an example of how life-forms we have already discovered are capable of the unexpected, even the seemingly impossible. With a little extrapolation and imagination, the possibilities only increase. So let's give the Drayan, of whom we know so little, the benefit of the doubt.

A Possibility from within the Already Established Star Trek Universe
On the other hand, by the time "Innocent" first aired, the Star Trek universe had already introduced us to a species that produces full-grown offspring, albeit in a manner that is somewhat more conventional than the sponge-inspired speculation mentioned above.

The seventh season TNG episode "Liaisons" introduced an obscure alien race called the Iyaaran. One of the Iyaaran envoys reacts in total shock when he sees a child walking through the corridor of the Enterprise. On one hand it is hard to imagine that a space-faring civilization had never encountered a race that gives birth to small children before, but on the other hand it does establish that there other kinds of reproduction in the Star Trek universe.

He explains that their offspring mature in a 'natal pod' outside of their parents. So while they evidently start small and get bigger in terms of reproduction and gestation, the Iyaaran are "born" fully grown. It is conceivable that the Drayan have a similar method of reproduction. It would certainly give us a fitting starting point for their reverse aging.

Beyond Bio-Chemistry
In the brief description we get of their life-cycle, the Drayan leaders explains that their 'energy only remains cohesive for a limited number of years' from the time they are "created." It is possible that when she says "created" she is simply refering to pro-creation, but the word certainly evokes the idea of a moment where they simply come into existence.

Above I offered a theory on a biological possibility for this kind of coallesing. But in light of the statement about 'cohesive energy' the Drayan may indeed be "created" in a process that has more to do with the laws of quantum mechanics or sub-space phenomena than with bio-chemistry.

So perhaps their means of reproductioin is truly exotic and allows them to start life fully grown. They exist in a biological form for a number of years and then their energy is released.

One Last Option
One other possibility is that the Drayan do produce offspring in essentially the same way as other humanoid races. They may begin life as small babies and get bigger as they get older, until they reach a certain point when the reverse aging kicks in. If this is the case, perhaps there is something about the Drayan young-children that distinguishes them from the Drayan elder-children. Perhaps it is a difference that wouldn't even be obvious to outsiders but that is unmistakable to the Drayan themselves. In other words, when they are said to age in reverse, this may be a reference to the end of their life-cycle, not to their life-cycle as a whole.

When we put it all together—real world science, already established Trek science, and extrapolations thereof—there seems to be plenty of room in the Star Trek universe for the Drayan and some kind of reverse aging.

There are a few remaining unanswered questions about the history of the Drayan civilization. These questions relate back to their unusual life-cycle and will be discussed in a future post.

100 Years Young:
Part I: Musings About the Drayan Life-Cycle

Part II: Is Aging an Inevitable Biological Fact?

Part III: Can an Organism 'Grow' Smaller and Younger?
Part IV: The Drayan Civilization

Friday, November 03, 2006

100 Years Young - Is Aging an Inevitable Biological Fact?

100 Years Young:
Part I: Musings About the Drayan Life-Cycle

Part II: Is Aging an Inevitable Biological Fact?

Part III: Can an Organism 'Grow' Smaller and Younger?
Part IV: The Drayan Civilization

Regarding this first point, let me begin with the assertion that what we know as the aging process is not the fundamental truth we presume it to be.

I recently came across an intriguing short story called "Invariant" by John Pierce about a scientist who learns how to stop biological aging. As the story explains: "The regeneration of limbs in salamanders led to the idea of perfect regeneration of human parts. How, say, a cut heals, leavng not a scar, but a perfect replica of the damaged tissue. How in normal metabolism tissue can be replaced not imperfectly, as in an aging organism, but perfectly, indfinitely." (The story deals with some unexpected results of his research - you may want to find a copy of this story to see how it ends.)

The idea of "perfect regeneration" proposed in this short story back in 1944 is not as far-fetched as it might sound. Consider some recent comments from some leading minds in the field of human aging:
“We tend to think of ourselves and other animals in the same way we think of machines: wearing out is simply inevitable . . . . Biological organisms are fundamentally different from machines. The most fundamental defining characteristic of living organisms, in fact, may be their ability to repair themselves . . . .They are self-repairing: wounds heal, bones mend, illness passes . . . . Why, then, should [biological organisms] be subject to the same sorts of wear and tear as machines?”——Steven Austad, Harvard University biologist

“At the molecular level our protein molecules are subject to continuous turnover at a rate characteristic of each particular protein; we thereby avoid the accumulation of damaged molecules. Hence if you compare your beloved’s appearance today with that of a month ago, he or she may look the same, but many of the individual molecules forming that beloved body are different. While all the king’s horses and men couldn’t put Humpty Dumpty together again, nature is taking us apart and putting us back together every day.”——
Jared Diamond, evolutionary biologist

"If you understand the mechanisms of keeping things repaired, you could keep things going indefinitely."——
Cynthia Kenyon, professor and director of the Hillblom Center for the Biology of Aging, University of California, San Francisco (UCSF)
Far from being a well understood biological necessity, the mechanisms that cause aging are a poorly understood biological puzzle. The mystery of aging is touched on in the DS9 episode "In the Cards." Dr. Giger suggests that the only reason we dies is because of cellular boredom - our cells simply become bored of doing the same thing over and over and over again. So he devises a cellular regeneration and entertainment chamber to counteract the problem. While the presentation is tongue-in-cheek, the issue is genuine: Why should a self-repairing, self-replicating system die in the absence of disease or trauma?

Aging only seems an intuitive concept becuase inanimate things deteriorate over time and because life as we know it does the same. But the above quotations demonstrate that aging is actually counter-intuitive when we realize that—in terms of the molecules and cells inside us—we have perpetually young bodies. In theory, we should be, or at least could be, perpetually young organisms.

This brings us to a startling realization: Aging may not inevitable—it may in fact be a quirk of how life on earth behaves.

That is probably a difficult concept to accept. But science fiction can and should challenge our assumtions and expand our minds to explore possibilites outside of our ordinary experience. Moreover, there are organisms on earth that do not age in the traditional sense of the word. What is more, even present human biology demonstrates a capacity to be ageless.

The classic example of an eathly organism that is for all intents and purposes immortal is the amoeba. Amoeba's do not grow old and die—they just keep dividing . . . indefinitely. Think about it. An idividual amoeba might be killed by something in its environment, but otherwise it will divide in two, and in two, and in two . . . without ever "wearing out."

If these single celled organisms can divide indefinitely (in fact, they must be able to do so for the species to survive), theoretically couldn't the individual cells within a larger organism do the same thing?

Actually they can—the cells in the human body already do this, in a manner of speaking.

A child's body is made up of cells that ultimately originate with its parents. Because the child has its own life—because we view it as a discreet organism in and of itself—it is easy to overlook the fact that our offspring are actually an extension of our own bodies. In a sense they are us. An aging human body can create, from its own cells, a perfectly vibrant, healthy, functional, youthful body.

We wouldn't even exist if the human body couldn't generate youthful cells. That would make us incapable of reproducing. These new and youthful cells make up every coneivable tissue and system of the human body. Couldn't those same mechanisms be used internally to replace older cells in our own bodies? If you can make youthful skin, or a heart, or a brain for your offspring, why can't you make them for yourself? The "stuff" we're made of keeps living indefinitely outside of us in our offspring and their offspring. Surely that "stuff" can live indefintely inside of us as well.

Being multi-cellular obscures it, but in the end we're really not that different from the amoebas. Our ability to reproduce proves we have the capacity to be ageless. And if the possibility of ageless life exists in our real universe, there certainly must be room for the possibility of a species like the Drayan in a fictional universe extrapolated from our own.

Beyond the issue of aging, we also need to address the process of growth that goes along with it. This will be discussed in my next post.

100 Years Young:
Part I: Musings About the Drayan Life-Cycle

Part II: Is Aging an Inevitable Biological Fact?

Part III: Can an Organism 'Grow' Smaller and Younger?
Part IV: The Drayan Civilization